<div class="card ">
    <div class="card-header">Ввод данных</div>
    <div class="card-body">
        <form action="/calc" method="post">
            {% csrf_token %}
            <div class="form-group form-row">
                <div class="col col-form-label">{{ form.first.label }}:</div>
                <div class="col">{{ form.first }}</div>
            </div>
            <div class="form-group form-row">
                <div class="col col-form-label">{{ form.second.label }}</div>
                <div class="col align-items-center">{{ form.second }}</div>
            </div>
            <div class="form-row">
                <div class="col">
                    <input type="submit" class="btn btn-primary float-right btn-block" value="Вычислить">
                </div>
            </div>
        </form>
    </div>
</div>